1. Field of the Invention
This invention relates to a technology of recovering voltage of a primary cell that has been used once. It discloses a method of recovering voltage of a primary cell which contains residual capacitance so that the primary cell can take up complete reactions of its electrolyte substance.
2. Description of the Prior Art
As information and communication industries have been growing, various electronic products, appliances and installations devices have also been widely developed and used. The power source of these electronic products and appliances largely depend on cells or batteries, which have been used more and more widely.
As to the cells and batteries, they are mostly classified into the following varieties according to their discharge characteristics.                1. A primary cell is a battery that can be used only once and cannot be charged and recharged repeatedly by supplementing transformed chemical energy. The primary cells include dry batteries, mercury batteries and alkaline batteries, etc. It is used earliest, and most widely, and those batteries being offered in the market are all belonging to this type of battery, such as button-shaped mercury batteries No. 1, 2 and 3.        2. A secondary battery can be charged and recharged repeatedly for repeating us age by recovering the active substance in the battery to its original condition so that the battery can supply electricity again. This type of batteries include a lead acid battery, a nickel cadmium battery, a nickel hydrogen battery, a secondary lithium battery, and a lithium ion battery, a polymer lithium battery, etc.        3. A fuel cell is greatly different from those two types as mentioned above, also known as a sustainable cell. It contains a negative pole and a positive pole without active substance, and only when it is supplied with active substances via an exterior system, it can discharge sustainable electric power. The positive pole consists of air or oxygen for the chemical reactions. The negative pole mainly consists of hydrogen or coal gas. The hydrogen-oxygen fuel cell belongs to this type of battery and is still under development. Limited by its large dimensions, it is mainly used for generators or spare power energy. Owing to recent technological advancement, its large size has been diminished gradually, and has come to be applied to electric vehicles.        
However, most of the common primary cells are either zinc manganese cells, dry batteries, or carbon zinc batteries, with the zinc used as a positive pole and the carbon bars plus manganese dioxide being used as a negative pole, and the ammonium chloride, zinc chloride, or starch used as an electrolyte. It supplies voltage 1.5 V or so under 25° C., and was early developed and discovered by a Frenchman named C. Lechance. In spite of its early discovery, it is cheap to make, easily made, discharge itself in a very low extent, having a high weight-energy ratio (50-60 Wh/Kg) and being handy to be carried. It is still made mostly and widely as a primary cell in nowadays.
This kind of primary cell has a drawback of low power, even if it has been developed quite early, so it is impossible to be applied to electric appliances using large current. Besides, there is a problem of unstable voltage in discharge. In addition, zinc manganese dry batteries may have its start voltage having a tendency to become fluctuated because of long storage time and different property of manganese dioxide of the negative pole, generally in the scope of 1.50V-1.80V. If electrolytic manganese dioxide is used, the voltage and capacity of the cell can be enhanced owing to its purity and high activeness.
Next, it should be noted that it is considerably important to preserve zinc manganese dry batteries. Its positive pole of zinc may erode and cause self-discharge in case of storing in a very wet environment. Moreover, a good sealing of the batteries matters significantly, and water in the electrolyte may evaporate out in case of bad sealing to result in impossible discharge. On the other hand, the batteries may discharge seriously if oxygen enters them.
Mercury batteries are another primary cells, and it is an alkaline battery because electrolyte is alkaline, shaped as a button or a cylinder. Its negative pole is made of 90% zinc powder and 10% mercury, and its positive pole is made of 80-95% mercury oxide mixed with, 5-15% graphite, with electrolyte made of 35-40% potassium hydroxide. This type of batteries discharges stably, with the start voltage being extremely stable, easy to store, having high dimension-energy ratio, discharging 1.34V under 25° C., so it is applicable to hearing aids or cameras.
According to the traditional knowledge and technology, the primary cell is considered to be impossible to be charged repeatedly. So primary cells produced according to the regulations of the industrial association are non re-chargeable limited by the active substance and the principle of electrical theory. Cells have to be manufactured according to the regulations, to pass the test required by the regulations, as a primary cell cannot pass the test to become qualified unless the content released by the chemical substance in the primary cell gets to the standard quantity in a set time. At this time, the chemical substance reacts and burns completely, and the chemical substance can produce no more energy.
By the way, existing electric appliances cannot be started by voltage in the range of 1.0V-1.2V, for example, MP3 players need an average of 1.15V of a single cell to be activated, and cannot be started for playing if the cell has less than 1.15V. Then a consumer may think the cell has no more electricity, and it has to be replaced with a new one. But in fact, although the cell cannot start the electric appliance but it still has a voltage of approximately 1.15V, and the chemical substance does not completely react, not that its electricity is completely used up.
The above condition of so-called non-electricity of a cell is totally different from the condition of no electricity that electric professionals and scholars deem. Because 1.15V is not tantamount to 0V, and it is unreasonable to decide if the cell can still be charged or not, with the meter connected to the cell at 0V. Almost all of the consumers cannot use a meter to measure capacitance of a used cell, and may think the cell is of no electricity. Nevertheless, a cell of insufficient capacity and impossible to start an electric appliance is useless to a consumer.
As can be understood by the description above, theoretically, it is true that a primary cell is not re-chargeable, but it is also true that when the chemical substance of a used cell is not completely used, there is still some electric capacitance remains. There is not a product that can make a used cell with its remaining capacitance, so consumers waste cells and bucks, resulting in a mountain of waste batteries.
Therefore, it is critical issue to recover voltage of used primary cells with some capacitance remained so as to repeatedly use them by permitting the chemical substance to react completely.